1. Field of Invention
The current invention relates generally to apparatus, systems and methods for connecting fabric together. More particularly, the apparatus, systems and methods relate to connecting flexible fabric together using heat. Specifically, the apparatus, systems and methods provide for connecting two flexible pieces of fabric together and controlling the welding heat, speed of the fabric and cooling air at a corner fold between the two pieces of fabric.
2. Description of Related Art
Heat welding has long been used to join waterproof sheet materials together to manufacture a variety of products such as tents, tarpaulins, liners for pools and landfills, awnings, military products and others. During the manufacturing process, two or more panels of flexible industrial fabric or technical textile, such as vinyl, are joined together into a single sheet. This is accomplished by overlapping sections of the panels of fabric and then applying heat and pressure to the overlapped sections to weld the materials together and form a seam. This procedure permits longer panels of the sheet materials to be produced so that the desired end product may be fabricated out of the same.
Various techniques have been developed to join sheet materials of this nature together. These include hot air welding, hot wedge welding and impulse welding. In hot air welding a nozzle is positioned so as to blow heated air between the two layers of sheet material. Typically, for a thermoplastic sheet material, the temperatures involved range anywhere from 200 F to 1,350 F (90 C to 750 C). Once the heat has been introduced between the layers, a roller passes over the same, applying a preset level of pressure to the layers. The combination of the heat and pressure joins the two panels of sheet materials together. Hot air welding requires precise temperatures and pressure to be applied to the sheet materials and also requires that the process be done in a timely fashion in order to prevent cooling of the sheet materials before the roller passes over the same.
Hot wedge welding is fairly similar to hot air welding, with the exception that instead of a nozzle being used to introduce heat into the system, a heated wedge is used. The wedge is positioned so that the fabric layers are pulled over the wedge immediately before they are contacted by the rollers. Wedges are typically heated to a temperature of between 200 F and 920 F (90 C and 490 C). Once again, the temperature, pressure and time have to be closely monitored in order to create a good seam.
While these approached to connecting two piece of fabric together work well when the seam is a continuous straight seam, they do not perform as well when a seam is curved or needs to form an angled turn such as at a 90 degree corner. Therefore, what is needed is a better way of connecting two pieces of fabric together.